Stackable block



FIG. 1 is a front view of a first embodiment of the stackable block showing the new design;

FIG. 2 is a back view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a top view thereof;

FIG. 6 is a bottom view thereof;

FIG. 7 is a top perspective view thereof.

FIG. 8 is a front view of a second embodiment of the stackable block showing the new design;

FIG. 9 is a back view thereof;

FIG. 10 is a left side view thereof;

FIG. 11 is a right side view thereof;

FIG. 12 is a top view thereof;

FIG. 13 is a bottom view thereof;

FIG. 14 is a top perspective view thereof.

FIG. 15 is a front view of a second embodiment of the stackable block showing the new design;

FIG. 16 is a back view thereof;

FIG. 17 is a left side view thereof;

FIG. 18 is a right side view thereof;

FIG. 19 is a top view thereof;

FIG. 20 is a bottom view thereof; and,

FIG. 21 is a top perspective view thereof. 

CLAIM I claim the ornamental design for the stackable block, as shown and described. 